Evaporative coolers are relatively simple cooling devices that provide a substantial amount of relief in arid regions, such as the southwestern United States. Evaporative coolers pump relatively dry atmospheric air through water-soaked filter pads. The latent heat of evaporation is transferred to the water, transforming hot, dry air into cool, moist air.
Typical evaporative cooler designs are able to come within 10° F. of the wet-bulb temperature, which is the minimum temperature that may be achieved by evaporative cooling. Because evaporative cooling is less expensive than typical air conditioning methods, several attempts have been made to increase the efficiency of the device in order to more closely approximate the wet-bulb temperature.
Designs currently available attempt to increase the efficiency of evaporative cooling by adding insulating and reflecting panels to the frame of the apparatus. This keeps external effects on the system, such as heat from solar radiation, to a minimum.
Other available improvements include the addition of an indirect evaporative cooling stage. In effect, the indirect evaporative cooling stage uses water as the heat exchange medium in a heat exchanger to lower the temperature of the air without adding humidity. Then, when the cooler air is passed through the evaporative cooling system, the resulting temperature of the air is closer to the wet-bulb temperature.
These developments have yielded a modest increase in efficiency. But, due to growing concerns about the environment and the rising costs of energy consumption, there remains a substantial need for improved evaporative cooling systems and methods.